java.lang.NullPointerException
at org.jboss.cache.invocation.NodeInvocationDelegate.clearDataDirect(NodeInvocationDelegate.java:243)
at org.jboss.cache.commands.write.ClearDataCommand.perform(ClearDataCommand.java:79)
at org.jboss.cache.interceptors.CallInterceptor.invokeCommand(CallInterceptor.java:108)
at org.jboss.cache.interceptors.CallInterceptor.handleAlterCacheMethod(CallInterceptor.java:173)
at org.jboss.cache.interceptors.CallInterceptor.visitClearDataCommand(CallInterceptor.java:149)
at org.jboss.cache.commands.write.ClearDataCommand.acceptVisitor(ClearDataCommand.java:86)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.EvictionInterceptor.visitClearDataCommand(EvictionInterceptor.java:235)
at org.jboss.cache.commands.write.ClearDataCommand.acceptVisitor(ClearDataCommand.java:86)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.MVCCLockingInterceptor.handleClearDataCommand(MVCCLockingInterceptor.java:124)
at org.jboss.cache.interceptors.base.PrePostProcessingCommandInterceptor.visitClearDataCommand(PrePostProcessingCommandInterceptor.java:167)
at org.jboss.cache.commands.write.ClearDataCommand.acceptVisitor(ClearDataCommand.java:86)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.ReplicationInterceptor.handleCrudMethod(ReplicationInterceptor.java:150)
at org.jboss.cache.interceptors.ReplicationInterceptor.visitClearDataCommand(ReplicationInterceptor.java:137)
at org.jboss.cache.commands.write.ClearDataCommand.acceptVisitor(ClearDataCommand.java:86)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.base.CommandInterceptor.handleDefault(CommandInterceptor.java:131)
at org.jboss.cache.commands.AbstractVisitor.visitClearDataCommand(AbstractVisitor.java:80)
at org.jboss.cache.commands.write.ClearDataCommand.acceptVisitor(ClearDataCommand.java:86)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.TxInterceptor.replayModifications(TxInterceptor.java:501)
at org.jboss.cache.interceptors.TxInterceptor.handleRemotePrepare(TxInterceptor.java:388)
at org.jboss.cache.interceptors.TxInterceptor.visitPrepareCommand(TxInterceptor.java:134)
at org.jboss.cache.commands.tx.PrepareCommand.acceptVisitor(PrepareCommand.java:68)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.base.CommandInterceptor.handleDefault(CommandInterceptor.java:131)
at org.jboss.cache.commands.AbstractVisitor.visitPrepareCommand(AbstractVisitor.java:140)
at org.jboss.cache.commands.tx.PrepareCommand.acceptVisitor(PrepareCommand.java:68)
at org.jboss.cache.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
at org.jboss.cache.interceptors.InvocationContextInterceptor.handleAll(InvocationContextInterceptor.java:178)
at org.jboss.cache.interceptors.InvocationContextInterceptor.visitPrepareCommand(InvocationContextInterceptor.java:106)
at org.jboss.cache.commands.tx.PrepareCommand.acceptVisitor(PrepareCommand.java:68)
at org.jboss.cache.interceptors.InterceptorChain.invokeRemote(InterceptorChain.java:316)
at org.jboss.cache.commands.remote.ReplicateCommand.processSingleCommand(ReplicateCommand.java:139)
at org.jboss.cache.commands.remote.ReplicateCommand.perform(ReplicateCommand.java:115)
at org.jboss.cache.marshall.CommandAwareRpcDispatcher.executeCommand(CommandAwareRpcDispatcher.java:319)
at org.jboss.cache.marshall.CommandAwareRpcDispatcher.handle(CommandAwareRpcDispatcher.java:246)
at org.jgroups.blocks.RequestCorrelator.handleRequest(RequestCorrelator.java:637)
at org.jgroups.blocks.RequestCorrelator.receiveMessage(RequestCorrelator.java:545)
at org.jgroups.blocks.RequestCorrelator.receive(RequestCorrelator.java:368)
at org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.up(MessageDispatcher.java:775)
at org.jgroups.JChannel.up(JChannel.java:1336)
at org.jgroups.mux.Multiplexer$Task.run(Multiplexer.java:1185)
at org.jgroups.mux.Multiplexer$ExecuteTask.run(Multiplexer.java:1208)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

Unfortunately not, I'm not involved enough in the JCR code and JBoss Cache usage to know what exactly is going on, I just did some initial investigation to know if it was an issue with eXo JCR or JBoss Cache. And it looks like